Gina

No, I mean mqtt-explorer that you suggested above.

OK - I've installed it but where is it? It's not in the menu.

I'll look into that - thanks Wim 😀

This tutorial uses Node-RED installed on the RPi running the broker to provide a graphical interface on a browser. Seems reasonable for the first setup. Later I may use WeeWX but guess there's not really a limit and I could have both. Any comments?

Ran the Arduino and went to Tools > Manage Libraries, searched for PubSubClient and Installed it. I already have the Adafruit_BME280 and Adafruit_Sensor libraries installed

This would seem to be what I want for the ESP32 and BME280 :- ESP32 MQTT – Publish and Subscribe with Arduino IDE

So far so good but I shall only feel I have it working when I have a separate client SBC talking to a client on the RPi or better still on something else. I have another BME280 which I can put on some stripboard with one of the ESP32s and program to read the indoor temperature, humidity and atmospheric pressure and send it to the broker. Then I can subscribe to new topics and send data. That way I can try out the MQTT system without venturing out to the obsy in a deluge and also leave the sensors working for real use.

I've GOT IT!! 😀 Each command has to be on a separate SSH connection to the broker. The first Terminal is just sitting there waiting for messages from clients. When another terminal is opened and SSH'd to the broker subscribing to "test" and sending the message "Hello", then "Hello" appears in the first Terminal. pi@MQTTBrokerGina:~ $ mosquitto_sub -h localhost -t “test” “Hello” The MQTT system is working albeit with broker and clients on the same machine (RPi). 😀

Tried rebooting - not solved it though. pi@MQTTBrokerGina:~ $ sudo reboot Connection to mqttbrokergina closed by remote host. Connection to mqttbrokergina closed. gina@Mint-Desktop ~ $ ssh pi@MQTTBrokerGina pi@mqttbrokergina's password: Linux MQTTBrokerGina 5.4.51+ #1333 Mon Aug 10 16:38:02 BST 2020 armv6l The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. Last login: Fri Aug 14 17:45:07 2020 from 192.168.1.79 pi@MQTTBrokerGina:~ $ mosquitto_sub -h localhost -t “test” And there it sits doing nothing! Evidently I'm not understanding this. Can someone please tell me what I'm doing wrong?

OK... Running this sequence :- Sections 1. to 3. completed. In section 3. ifconfig confirms the IP address as correct. In section 4. I copied the command into the Terminal but nothing happened. Does the RPi need rebooting or am I completely misunderstanding this?

Next job is :- Setup MQTT Server on Raspberry Pi Zero This installs both the Mosquitto broker and clients so the RPi can be used as both broker and a client. I may use it for either the indoors sensors or the mechanical weather wall display with several dials and gauges. Thinking of the latter as the RPi has lots of GPIO pins.

That completes setting up the Pi Zero W for headless SSH access over WiFi.

Now running the usual :- sudo apt-get update -y sudo apt-get upgrade -y

That was it - I'm in 😀 gina@Mint-Desktop ~ $ ssh pi@MQTTBrokerGina The authenticity of host 'mqttbrokergina (192.168.1.250)' can't be established. ECDSA key fingerprint is SHA256:eH9cpckOI0MiUwVEkp18LQ17PoYs0DoJtoLHcePf5yg. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'mqttbrokergina' (ECDSA) to the list of known hosts. pi@mqttbrokergina's password: Linux MQTTBrokerGina 4.19.118+ #1311 Mon Apr 27 14:16:15 BST 2020 armv6l The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. Last login: Fri Aug 14 16:38:52 2020 from 192.168.1.79 pi@MQTTBrokerGina:~ $

Looks like another restart!! Maybe it doesn't like that host name. Checking Network Clients on router... Aha - no underlines.

Not surprisingly, I think I've done something wrong in changing host name and password. I decided on a host name of MQTT_Broker_Gina though this system seems to ignore case unlike most Linux systems. gina@Mint-Desktop ~ $ ssh pi@raspberrypi The authenticity of host 'raspberrypi (192.168.1.250)' can't be established. ECDSA key fingerprint is SHA256:eH9cpckOI0MiUwVEkp18LQ17PoYs0DoJtoLHcePf5yg. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'raspberrypi' (ECDSA) to the list of known hosts. pi@raspberrypi's password: Linux raspberrypi 4.19.118+ #1311 Mon Apr 27 14:16:15 BST 2020 armv6l The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. SSH is enabled and the default password for the 'pi' user has not been changed. This is a security risk - please login as the 'pi' user and type 'passwd' to set a new password. pi@raspberrypi:~ $ sudo raspi-config New password: Retype new password: passwd: password updated successfully Welcome to fdisk (util-linux 2.33.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): Disk /dev/mmcblk0: 14.9 GiB, 15931539456 bytes, 31116288 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x55d719e5 Device Boot Start End Sectors Size Id Type /dev/mmcblk0p1 8192 532479 524288 256M c W95 FAT32 (LBA) /dev/mmcblk0p2 532480 31116287 30583808 14.6G 83 Linux Command (m for help): Partition number (1,2, default 2): Partition 2 has been deleted. Command (m for help): Partition type p primary (1 primary, 0 extended, 3 free) e extended (container for logical partitions) Select (default p): Partition number (2-4, default 2): First sector (2048-31116287, default 2048): Last sector, +/-sectors or +/-size{K,M,G,T,P} (532480-31116287, default 31116287): Created a new partition 2 of type 'Linux' and of size 14.6 GiB. Partition #2 contains a ext4 signature. Command (m for help): Disk /dev/mmcblk0: 14.9 GiB, 15931539456 bytes, 31116288 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x55d719e5 Device Boot Start End Sectors Size Id Type /dev/mmcblk0p1 8192 532479 524288 256M c W95 FAT32 (LBA) /dev/mmcblk0p2 532480 31116287 30583808 14.6G 83 Linux Command (m for help): The partition table has been altered. Syncing disks. Connection to raspberrypi closed by remote host. Connection to raspberrypi closed. gina@Mint-Desktop ~ $ ssh pi@raspberrypi ssh: Could not resolve hostname raspberrypi: Name or service not known gina@Mint-Desktop ~ $ ssh pi@MQTT_Broker_Gina ssh: Could not resolve hostname mqtt_broker_gina: Name or service not known gina@Mint-Desktop ~ $

OK. SSH into RPi Zero and change of host name and password done plus file system expanded. Now to try SSH with new host name and PW.

I certainly could though what I have in mind is a bit different. I want temperature, humidity, wind speed, wind direction, rainfall, rain status, cloud status, etc. in addition to pressure and its trends. Trouble is lack of free wall space. The space above the fireplace has a giant clock with 3ft dial and many of my watercolour paintings plus router and WiFi AP. East wall also has paintings and my moon dial clock plus a large bookshelf and air-con unit. And a window, vintage barometer etc.

I think it's back to square one! Or almost. I have the OS in my downloads and the supplicant data in the editor. Seems I won't need keyboard or monitor connected to the RPi Zero.

Got as far as password again. gina@Mint-Desktop ~ $ ssh 192.168.1.250 The authenticity of host '192.168.1.250 (192.168.1.250)' can't be established. ECDSA key fingerprint is SHA256:lEMA9QPPY5y8I57L7qlLbXpK95DZXF8hlbdZJJPvtd0. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.1.250' (ECDSA) to the list of known hosts. gina@192.168.1.250's password: Permission denied, please try again. gina@192.168.1.250's password: Permission denied, please try again. gina@192.168.1.250's password: Where is the user password stored? Can I change it by editing a file? Or do I have to start again and use the default PW "raspberry". Neither that or the one I set up now work.

Put empty file SSH into boot directory and made wpa_supplicant.conf file with the info in it. gina@Mint-Desktop / $ cd media gina@Mint-Desktop /media $ ls gina gina@Mint-Desktop /media $ cd gina gina@Mint-Desktop /media/gina $ ls 3630-3533 512-NTFS-1 512-NTFS-2 6363-3732 boot rootfs ssdata2 gina@Mint-Desktop /media/gina $ cd boot gina@Mint-Desktop /media/gina/boot $ ls bcm2708-rpi-b.dtb COPYING.linux LICENCE.broadcom bcm2708-rpi-b-plus.dtb fixup4cd.dat overlays bcm2708-rpi-cm.dtb fixup4.dat ssh bcm2708-rpi-zero.dtb fixup4db.dat start4cd.elf bcm2708-rpi-zero-w.dtb fixup4x.dat start4db.elf bcm2709-rpi-2-b.dtb fixup_cd.dat start4.elf bcm2710-rpi-2-b.dtb fixup.dat start4x.elf bcm2710-rpi-3-b.dtb fixup_db.dat start_cd.elf bcm2710-rpi-3-b-plus.dtb fixup_x.dat start_db.elf bcm2710-rpi-cm3.dtb issue.txt start.elf bcm2711-rpi-4-b.dtb kernel7.img start_x.elf bootcode.bin kernel7l.img wpa_supplicant.conf cmdline.txt kernel8.img config.txt kernel.img gina@Mint-Desktop /media/gina/boot $ Now to see if it works. ie. if I can SSH into the RPi Zero.

Have microSD card in card reader and there's no SSH file and no wpa_supplicant.conf and yet I had SSH working over WiFi on the RPi 3B+. Guess the problem I had deleted these.

I'll check the data on the card. I thought of a wired connection but when I came to plug the Ethernet cable into the RPi - lo and behold - no Ethernet port, so it has to be WiFi.

👍

The RPi Zero has arrived. Not sure I can use it yet though as I'm waiting for delivery of a mini HDMI cable. Depends if it will work with the microSD card I produced for the RPi 3B+ Have to say, I'm impressed with The Pi Hut - with RM 24 delivery.